This application claims the priority of Korean Patent Application No. 2003-92504, filed on Dec. 17, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an optical device, and more particularly, to an optical device including, as an integral unit, an optical waveguide for guiding light and an optical detector for detecting the light, and a method of manufacturing the same.
2. Description of the Related Art
Recently, an optical communication network, which connects optical fibers to a plurality of subscriber terminals, has been actively studied so as to embody a high speed optical communication network. In addition, optical communication subscriber test networks have been established and operate in some regions so as to more widely spread optical communication.
An optical transceiver is essential for establishing such an optical communication network. The optical transceiver converts a digitalized electrical signal into an optical signal within a predetermined wavelength band, transmits the optical signal through an optical fiber, detects the optical signal within the predetermined wavelength band received through the optical fiber, and converts the optical signal back into a digitalized electrical signal.
FIG. 1 is a cross-sectional view of a conventional optical device integrally including an optical waveguide and an optical detector as portions of a receiver section of the optical transceiver.
Referring to FIG. 1, the conventional optical device 10 having an optical waveguide and the optical detector includes a silicon substrate 12, an optical waveguide 15 and an optical detector 20 made of InGaAs. The optical waveguide 15 includes a first clad layer 14 made of SiO2, a core layer 16 made of SiO2:Ge and a second clad layer 18 made of SiO2. The first clad layer 14, the core layer 16 and the second clad layer 18 are sequentially formed on a predetermined region of the silicon substrate 12.
The conventional optical device 10 is manufactured using a hybrid integration method in which the optical detector 20 is finely adhered on a predetermined position of a silicon substrate 12 having the optical waveguide 15 thereon using a flip-chip bonding technique.
The hybrid integration method, however, makes the entire manufacturing process complex and lowers production yield. This is due to misalignment of core layers of an optical waveguide and an optical detector.
As a consequence, because much time and effort is required for fine alignment to thereby partially solve the above problems, and because expensive equipment is also necessary, the ability to reduce manufacturing cost is limited.
Furthermore, the separately manufactured optical detector is fabricated using a compound semiconductor suitable for a commonly used wavelength band. The substrate employed in the optical detector not only is expensive, but it is also difficult to lower production cost where mass production is limited by wafer diameter.